Abstract
Plastics and glasses are materials traditionally used to transmit light
in optical data transmission applications. Sol-gel technique takes advantage
of the best parts from both materials. It is a technique, where solid
organic/inorganic hybrid glass materials can be derived from a liquid phase
and can have a wide variety of properties.
Target for this thesis was to study sol-gel based passive optical waveguide
materials for planar optical applications. Their usefulness in optics has been
studied widely, but quite often these materials are not suitable due to high
C-H and O-H contents. These bonds and especially O-H bonds cause strong
absorption loss at telecommunication wavelength windows, which are around 1310
and 1550 nanometers. Therefore, materials were synthesised to contain these
bonds as low amount as possible.
Several optical waveguide materials were synthesised within the framework of
this thesis. Two of them were optically characterised (refractive indices,
birefringences and optical losses) to study their applicability for planar
optical applications. Raman technique was employed to study reaction kinetics
in one system. In addition, a fluorinated silane precursor was synthesised and
characterised by nuclear magnetic resonance (NMR). Fluorination (C-H to C-F)
decreases optical losses in sol-gel waveguide materials. Other ways to
decrease optical losses are deuteration (C-H to C-D) and chlorination (C-H to
C-Cl).
Best results were achieved with chlorinated materials. Surface roughness of
the planar waveguide structure (slab structure) was 3 nanometers. Optical
losses of the waveguide were around 1 dB/cm at 1310 and 1550 nm wavelengths
and around 0.4 dB/cm at 830 nm wavelengths. Film thickness for the same
material was approximately 4 micrometers.
Original language | English |
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Qualification | Master Degree |
Awarding Institution |
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Place of Publication | Oulu |
Publisher | |
Publication status | Published - 2003 |
MoE publication type | G2 Master's thesis, polytechnic Master's thesis |
Keywords
- Sol-gel
- planar optical waveguide